System for communicating with a subject and/or for supervision of the subject during magnetic resonance imaging (mri), camera module, control unit, receiving and sending unit and optical transmission system

ABSTRACT

Disclosed is a system (100, 200) for communicating with a subject and/or for supervision of a subject during magnetic resonance imaging (MRI), comprising: a camera device (110, 210) that is configured to be placed within an interior space (194) of an MRI device (192), an optional optical output device (120, 220) for generating electromagnetic radiation in the visible spectral range that is configured to be placed within the interior space (194) of the MRI device (192), and -an electronic control unit (130, 230) that is configured to be placed within a distance less than 5 meters or less than 3 meters from the MRI device and/or from the optional optical output device (120, 220) and/or from the camera device (110, 210), wherein the optional optical output device (120, 220) is configured to be arranged within the field of view of a subject who is located within the interior space (194) and wherein the optional optical output device (120, 220) is configured to send optical signals (Si1, Si2) to the subject, wherein the electronic control unit (130, 230) is configured to control operation of the camera device (110, 210) and/or of the optical output device (120, 220).

System for communicating with a subject and/or for supervision of the subject during magnetic resonance imaging (MRI), camera module, control unit, receiving and sending unit and optical transmission system

DESCRIPTION

The disclosure relates to a system for communicating with a subject and/or for supervision of the subject during magnetic resonance imaging (MRI), a camera module device, a control unit, a receiving and sending unit and to an optical transmission system.

Known MRI devices are used to examine heads of persons or patients or other parts of the body. MRI may be used not only for humans but also to make images of the body of animals. An fMRI (functional MRI) may be used to examine or to study processes within the brain, for instance which areas are active if a special task has to be solve, if special associations are evoked or if language has to be processed.

Electromagnetic waves that are used to take an image with an MRI device may be within a range of for instance 1 MHz to 300 MHz (radio, television band). Certain atomic nuclei are able to absorb and emit radio frequency energy when placed in an external magnetic field. In clinical and research MRI, hydrogen atoms are most often used to generate a detectable radio-frequency signal that is received by antennas in close proximity to the anatomy of the subject being examined. Hydrogen atoms are naturally abundant in people and other biological organisms, particularly in water and fat of a living body. For this reason, most MRI scans essentially map the location of water and fat in the body. Pulses of radio waves excite the nuclear spin energy transition, and magnetic field gradients localize the signal in space. By varying the parameters of the pulse sequence, different contrasts may be generated between tissues based on the relaxation properties of the hydrogen atoms or other atoms or molecules therein. The field strength of the magnetic field that is used in MRI devices is for instance within the range from 0.5 T (Tesla) to 10 T, especially within the range from 1 T to 5 T. Examples are for instance devices operating with a field strength of 0.9 T, 1.5 T, 3 T or 7 T.

For example, the head of the subject has to be placed within a narrow tube of the MRI device. This makes it difficult to take for instance optical images or a video stream of the face of the subject. Furthermore, it is difficult to communicate with the subject during the MRI imaging process. Other persons are not allowed to be within the room in which the MRI device is located, especially during MRT (Magnetic Resonance Tomography).

It is an object of the invention to provide a simple and efficient system for communication/signaling with a subject and/or for supervision of the subject during magnetic resonance imaging (MRI). A further object of the disclosure is to provide an integrated system that allows inter alia time-precise signaling to the subject and/or visual control of the subject's performance for a variety of procedures. Another key factor may be to allow easy and flexible control over the proposed functionality. Furthermore a corresponding optical output device, control unit, receiving and sending unit and optical transmission system shall be disclosed.

This object is solved by the system according to claim 1. Further embodiments are given in the dependent claims. Furthermore, the object is solved by a camera module, a control unit, a receiving and sending unit and an optical transmission system.

In one aspect the system may comprise the following features:

-   -   a camera device that is configured to be placed within a gantry         of an MRI device,     -   an optional optical output device for generating electromagnetic         radiation in the visible spectral range that is configured to be         placed within the gantry (interior space) of the MRI device, and     -   an electronic control unit that is configured to be placed         within a distance less than 5 meters or less than 3 meters from         the MRI device and/or from the optical output device and/or from         the camera device,     -   an optional receiving and sending unit that can receive video         signal from the camera and send control signals to other         components of the system,

wherein the electronic control unit is configured to control operation of the camera device (optical) and/or of the optical output device.

The camera device may take images or pictures using optical sensors. Thus the camera takes images of areas of the subjects that are visible from outside. This is contrary to MRI images that show images of areas or space regions that are within the subject. The camera device may be used to give the examiner a feedback of the physical and psychological state of the subject. Furthermore, it is possible to define gestures and/or facial expressions in advance allowing the subject to actively communicate via the camera device with a person that is outside the MRI room.

The gantry may be the room in which the patient or subject or parts of him/her are placed during MRT. The gantry may form a ring, tube or hollow cylinder.

The optical output device may be configured to be arranged within the field of view of a subject who is lying within the gantry of MRI device. The optical output device may be configured to send optical signals to the subject. The electronic control unit is configured to control operation of the optical output device and/or of the camera device. Alternatively and or additionally, the electronic control unit may serve as a bridge that receives control signals from a receiving and sending unit and sends these control signals further to the optical output device and/or the camera device.

A simple communication in the direction from a control room to the subject may be possible using the optical output device. The optical output device may be small enough to be arranged within the narrow tube of the MRI device. Again, it is possible to define a meaning of special light colors and/or light sequences in advance. Green light may be used to signal that everything is OK or all right. A yellow light may have the function to indicate that images are taken and that the subject shall not move the body. Further, it may be sufficient and also pleasant and comfortable to see light in this narrow tube instead of pictures on a screen that would be too narrow in front of the eyes of the subject. Thus, a two way communication may be established using simple technical means. Furthermore, this communication may be precisely synchronized with an fMRI procedure, e.g. in order to measure reaction time of the subject to the stimuli. A further application is the signaling of the start of a task that the subject has to perform during MRT or before MRT.

The one way communication or the two-way communication may also be used if a part of the body of the subject is MRI scanned that is different from the head, for instance a leg, an arm or the abdomen.

The optical sensors of the camera device may have sensitivity in the range of 350 nm (nanometers) to 750 nm, i.e. in the visible range. However, infrared images/pictures may also be taken.

The optical output device may also radiate light in the range of 350 nm to 750 nm, i.e. within the visible range. The optical output device may radiate light into the area that forms the scene from which the camera device takes images/pictures or a continuous stream of images/pictures. Alternatively, the main radiation of the optical output device may be directed into an area that is different from the field of view of the camera.

In both cases, there may be a separate illuminating device that illuminates the scene that is relevant for a camera of the camera device. An example is the case in which the breathing frequency is monitored by the camera but the radiation of the optical output device is directed to the face of the subject.

The control device may be arranged within the vicinity of the optical output device and/or the camera device, for instance within a radius that is smaller than 3 meters. An examiner, a practitioner or another stuff person may control the images/pictures that are taken from the camera device using the control unit. If the field of view of the camera device is not sufficient or not appropriate there are only some steps to walk in order to change the position of the camera. It is also easy to test if the person may recognize the light that is radiated from the optical output device. If not, it is easy to change the position of the optical output device that may be located within the gantry of the MRI device or nearby.

The optical output device may be any source of light or any optical signaling source, for instance a lamp, a movable disc, an optoelectronic device, even a small screen. Optoelectronic devices may be preferred because they can give strong or bright light, light with changeable colors and/or do not radiate too much heat. The light of the optical output device may have only one color, i.e. radiate a small or narrow band of frequencies or wavelengths, for instance smaller than 50 nm or smaller than 20 nm if the FWHM (Full Width at Half Maximum) measurement is used. The light source of the optical output device may be arranged near the lens of the camera of the camera device, for instance within a distance that is less than 10 cm (centimeters) or less than 5 cm. Illumination lights may be arranged between the light source of the optical output device and the camera aperture. This may ease good recognition of the signaling light/source that may be part of the optical output device.

White light may be used to illuminate the scene that is in the field of view of the camera. This light may not be used for signaling during MRI imaging because it may be important to monitor the subject continuously using the camera device. Alternatively, the illuminating light may be an infrared light. Alternatively, the optical output device may comprise two kinds of illuminating lights, for instance white one and infrared one. The color of the illuminating light may be different from the color of the signaling light in order to ease recognition of the signaling light by the subject.

The proposed system may be removably placed within the MRI device, especially the optical output device and/or the camera device. Alternatively, the system may be an integral part of the MRI device.

The camera device and/or the optical output device and/or the control unit may be MRI protected and/or compliant with an operation within or close to an MRI device by any one of, any arbitrarily selected plurality of some or all of the following measures:

-   -   at least one current-source driven optoelectronic device of the         optical output device or at least one voltage controlled         current-source driven optoelectronic device, and/or     -   metal shielding of at least parts of the control unit and/or         optical output device, and/or     -   image data transmission to and/or from the camera device through         at least one optical fiber, and/or     -   control data transmission to and/or from the optical output         device through electrical control lines with additional filter,         and/or     -   control data transmission to and/or from the camera         device/optical output device through electrical control lines         with additional filtering, and/or     -   electrical filtering on power lines for powering the optical         output device and/or the camera device.

The MRI protection may be realized considering two directions. The first direction is that the devices do not disturb the MRI process, for instance by generating artifacts that are visible in the MRT (Magnetic Resonance Tomography) image. The other direction is that the MRI device does not disturb the operation of the devices of the proposed system. The devices of the proposed system may be shielded for instance with regard to electromagnetic waves, especially individually. Furthermore, single critical components may be shielded within a device of the proposed system, for instance a microprocessor, control circuits, transmission circuits and/or a camera sensor matrix. Copper, brass or other appropriate materials may be used as shielding materials.

Resistors combined with the capacitance of the circuits and/or with additional capacitors may create RC (Resistor Capacitor) filters. It is possible to empirically adjust the filters. Alternatively or additionally, results of circuit simulation may be used for adjustment.

The system may comprise an optical connection between the camera device and the control unit, and/or an electrical conductive connection between the optical output device and the control unit. Optical connections enable a signal/data transmission without significant interference with regard to the MRI device. Otherwise, an electrical conductive connection does not require signal conversions form optical to electrical and/or vice versa. Additional measures may be necessary for the transmission of data/signals via electrical conductive lines with regard to MRI compatibility in both of the directions that are mentioned above. A communication via power lines PLC may be used for control data transmission via electrical lines. This may reduce the number of wires or cables between the control unit and the optical output device. Alternatively, an electrical connection that is separate from a power line may be used for (control) data transmission between the control unit and the optical output device and/or the camera device.

Furthermore, it is alternatively possible to use only one connection between the control unit and the optical output module and/or the camera device, preferably an optical connection.

The optical connection between the camera device and the control unit may be the only one optical connection between the camera device and the control unit. This may simplify the system and may reduce costs of the overall system.

The electrical conductive connection may be used to transmit control signals to control camera settings and/or to control the optical output device, for instance switching on/off one or more signaling units, preferably of different colors or generating different colors using for instance a multicolor LED.

The system may comprise a receiving and sending unit that may receive video data generated by the camera device and that receives and/or sends control data. The system may comprise another (second) optical connection between the control unit and the receiving and sending unit. This second optical connection may be used for the transmission of video data as well as for the transmission of control data. Thus, no additional MRI protection is necessary with regard to the robust second optical connection. The second optical connection may be a bidirectional optical connection. Alternatively, a separate connection for control signals may also be used between the control unit and the receiving and sending unit.

The optical connection between the control unit and the receiving and sending unit may be the only one connection and/or only one optical connection between the between the control unit and the receiving and sending unit. This may simplify the system and may reduce costs of the overall system.

The receiving and sending unit may be located outside a room that comprises the MRI device. The second optical connection may go through a wall of the room that comprises the MRI device.

The receiving and sending unit may comprise an optical sending unit, an optical receiving unit, a radio transceiver circuitry and at least one interface unit, for instance to at least one computing device and/or to a video signal output. The transceiver circuitry may be connected to the optical sending unit and to the optical receiving unit. Furthermore, the transceiver circuitry may be connected to the interface unit. Alternatively the receiving and sending unit may be part of a computing device that may be used to store video data and/or to view video data and/or to input control commands.

The optical sending unit and the optical receiving unit within the sending and receiving unit may be of the same device type as optical sending/receiving units within the control unit and/or within the camera device in order to simplify part logistics.

The radio transceiver circuitry may be configured to perform a frequency shift keying and/or an amplitude shift keying, preferably in the radio frequency range. Frequency shift keying FSK and/or amplitude shift keying ASK are robust keying or modulations methods that enable data transmission with no or hardly any transmission errors even in environments with strong electrical/magnetic fields and/or high frequencies of these fields. Other modulation schemes and/or coding schemes may also be used.

The radio frequency range may comprise or consist of the range of 1 MHz to 300 MHz (radio, television band), more specifically the range of 10 MHz to 300 MHz or of 100 MHz to 300 MHz. The upper limit may be less than 250 MHz or less than 200 MHz.

A further radio transceiver circuitry may be used in the control unit. Both radio transceiver circuitries may be of the same device type. The transmission of control signals on the second optical connection may be a half-duplex transmission for example. Only one frequency of light may be used. Data may be sent via serial transmission. It is possible to use a master/slave mode. A master sends a ping signal to the slave. After the ping the slave has a specific time to send its data. Otherwise the master is sending its own data and the slave device is listening. The receiving and sending unit may be for instance the master device and the control unit may be the slave device. Alternatively, the control unit may be for instance the master device and the receiving and sending unit may be the slave device

An embodiment relates to an arrangement comprising the system or its embodiments mentioned above or below and an MRI device. The optical camera device and/or the optical output device and/or the control device may be installed at or on the MRI device or at least within the same room as the MRI device. The optional receiving and sending unit may be installed at a room that is outside the room with the MRI device. However, it is also possible that the proposed system or at least some of its parts are integral part of the MRI device. The room that is different from the room with MRI device may enable other persons to connect their working devices to the receiving and sending unit and to work the whole day there without entering the MRT room too often or without entering the MRT room at all.

The receiving and sending unit may be connected to at least one computing device, e.g. a tablet computer, a personal computer, a laptop computer, a workstation, a smartphone, etc. The computing device may be coupled permanently or only for a short time to the receiving and sending unit via a further connection, for instance a USB (Universal Serial Bus, preferably 2.0, 3.0 or higher), HDMI (High Definition Multimedia Interface), etc. However, it is also possible to use a wireless interface, for instance WLAN (Wireless Local Area Network). A further computing device may be a frame grabber or a device for displaying the images that are coded within the video data/video signal.

The receiving and sending unit and/or the computing device may be devices that have no additional MRI shielding/protection, i.e. there are no additional costs for realizing MRI protection/shielding for the measures that are listed above and that may be used for other units/devices of the proposed system.

For most operating systems OS (Operating System) software that may be used for the implementation of the interface of the system or that may be adapted is available, for instance a Virtual COM port for the operating system Windows (for instance Windows 10 or higher) and for USB connections. Alternatively similar software for USB or other transmission protocols may be used if other operating systems (UNIX, iOS, etc.) are used in the computing device.

Alternatively, image and/or video data storage and/or calculation capacity of the cloud may be used, i.e. capacities that are available in the internet or in private IP (Internet Protocol) networks, for instance a service of the company that owns the MRI device, i.e. a hospital, a practice, etc. or of a third side service provider.

A power supply unit may be used within the room that comprises the MRI device or within a different room. This power supply unit may be used to power the control unit and/or the optical output unit and/or the camera device. MRI shielding/protection may be realized for the power supply unit. The power supply unit may be independent of the power supply unit of the MRI device.

The power supply unit may detect the strength of the magnetic field, i.e. it may comprise a corresponding sensor element. The detected value of the magnetic field strength may be compared with a stored comparison value. If the detected value is greater and/or equal to the stored comparison value the power supply may switch off power supply to some of the components of the system for safety reasons. An indication of this state may be given, for instance using a signaling light, especially a red light. The comparison value may be in the range of 5 mT (milli Tesla) to 50 mT, for instance at 20 mT. Furthermore, all power lines may comprise additionally filter units. MRI shielding/protection may also be used in a power supply that comprises this switch off feature.

The system, especially the control unit may comprise an optical splitting unit that may comprise at least a first port, a second port, a third port and a fourth port:

-   -   the first port may be configured to be connected or is connected         to the or to an optical connection between the control unit and         the camera device,     -   the second port may be configured to be connected or is         connected to the or to an optical connection between the control         unit and the receiving and sending unit,     -   the third port may be configured to be connected or is connected         to the control unit, and     -   the fourth port may be configured to be connected or is         connected to the control unit

The optical splitting unit may be configured to forward image data or video data from the first port to the second port and/or to the fourth port, to forward control data from the third port to the second port and to forward control data from the second port to the fourth port. At least two optical splitting members or optical couplers may be used within the optical splitting unit. Thus signal doubling may be possible using simple technical means, especially no conversion of data between electrical and optical states. Furthermore, it is possible to save for instance a further sending unit. Signal processing load in the control unit for forwarding of electrical video data to other units can also be avoided.

The system may comprise a power line between the control unit and the optional optical output device and/or the camera device. The same power line may be used for powering the camera device and/or for data transmission to/from the camera device. Further, the same power line may be used to power the camera device and the optical output device.

The control unit may comprise the following units in order to enable the communication via the power line:

-   -   an electrical sending unit that may be configured to send data         by modulating the voltage over power line,     -   an electrical receiving unit that may be configured to receive         data by evaluating/sensing the current flow through the power         line,     -   a transceiver unit or functionality implemented preferably in         the program code loaded into a microprocessor, connected to the         electrical sending unit and to the electrical receiving unit,         preferably configured to implement a frequency shift keying         (FSK) data transmission method or a method comprising FSK, i.e.         a method that enables data transmission with low error rates         also in strong electrical/magnetic fields especially in fields         that alternate with high frequencies, for instance with         frequencies above 1 MHz (Megahertz), above 10 MHz.

The communication via the power line may control a controlled device, i.e. camera device and/or optical output device and/or illumination unit. This controlled device may comprise:

-   -   an electrical receiving unit , configured to receive data by         evaluating low amplitude changes of power voltage, and/or     -   an electrical sending unit configured to send data by changing         the changing the electrical load of the power line.

Low amplitude changes may mean less than 10 percent of offset voltage, e.g. operation potential or operation voltage.

Furthermore, the control unit may comprise:

-   -   an optical sending unit,     -   an optical receiving unit, and     -   a radio transceiver circuitry connected to the optical sending         unit and to the optical receiving unit, preferably configured to         implement a FSK data transmission method or a FSK/amplitude         shift keying (ASK).

Thus it is possible to combine power line communication PLC and optical communication for the transmission of control signals. Each segment of the communication connection may have its own requirements that are best met using PLC or optical transmission.

The control unit may comprise a control subunit that is configured to control the camera device and/or the optical output device and/or an illumination unit that is configured to illuminate a scene that is in the field of view of the camera device. The control subunit may be connected to the electrical sending unit and/or to the electrical receiving unit and/or to the radio transceiver circuitry.

The control unit may comprise a touchscreen. The touchscreen may be a very compact input and output device. Installation space may be limited near an MRI device. Usability of a touchscreen is high because the user interface UI may be adapted easily to the needs of the user and/or of the application.

Control of the camera device may comprise control of camera settings, e.g. f-number (may also be characteristic of lens or of lens system, i.e. it is fix), exposure time, image brightness, contrast, field of view, etc. Furthermore, a preview image may be provided on an output device of the control unit, for instance on a touchscreen, and/or outside of the MRI device room before the MRI procedure starts. Control of the camera device may be performed using the control unit (touchscreen) as an input device. Alternatively, a further device may be used that sends its control data to the control unit. The control unit may perform a conversion and/or forwarding of the control data, preferably in both directions of transmission.

Control of the optical output device may comprise converting the optical control data that comes from outside of the control unit to electrical control data. Alternatively, it may be possible to test the optical output device, specifically the signaling light, using the control unit as input device.

Control of the illumination unit may comprise selecting an appropriate brightness and/or selecting an appropriate light source, for instance IR-light (Infrared) or light within the visible range. Control of the illumination unit may be performed using the control unit (touchscreen) as an input device. Alternatively, a further device may be used that sends its control data to the control unit.

Thus, control of all settings or of most settings may be performed or may be also performed through a second control device (for instance a PC personal computer, etc.), for instance via USB. The second control device may be connected to the sending and receiving unit that is mentioned above.

The control subunit may be connected to the radio transceiver unit. The control subunit may perform forwarding of control data received at the optical receiving unit to the electrical sending unit. Furthermore. The control subunit may perform forwarding of control data in the other transmission direction, e.g. control (feedback) data that is received at the electrical receiving unit may be forwarded to the optical sending unit. The subunit may also forward control data that is generated in the control unit to the electrical sending unit.

Thus the control unit, especially the subunit, may act as a bridge for control signals that come from outside of an MRI device room, for instance from a control room. Control confirmation signals and/or control data from camera device and/or signaling device and/or illumination unit may also be forwarded or bridged in the other direction, e.g. to a room that is outside and MRI device room, for instance a control room or a technical (stuff) room.

The optical output device may comprise at least one low pass filter unit or at least two low pass filter units that may improve electromagnetic compatibility EMC.

At least one first low pass filter unit and at least one second low pass filter unit may be connected in this order along the direction of the signal flow from the control unit to at least one optoelectronic device that is comprised within the optical output device. The first low pass filter unit may have a higher cutoff frequency than the second low pass filter unit. Using two low pass filter units that are serially connected may enable very smooth filtering. The cutoff frequency of the first low pass filter unit may be in the range of 155 to 165 Hertz, preferably equal to 159 Hertz. The second low pass filter unit may have a cutoff frequency in the range of 140 to 150 Hertz, preferably equal to 146 Hertz. There may be a low pass filter unit or a group of serially connected low pass filter units for each “color cannel” respectively, i.e. for each optoelectronic device (LED, light emitting diode) that is controlled separately from other optoelectronic devices. Low pass filtering may be appropriate for a PWM (Pulse Width Modulation) signal that is used to control a voltage controlled current source that provides an operation current for the optoelectronic device preferably in a way that minimizes artifacts on MRI image, e.g. within a circuitry that reduces abrupt changes of the current flow as much as possible.

The optical output device may comprise at least one optoelectronic device that is configured to send the optical signals or at least a part of the optical signals to the subject that is examined using the MRI device. The at least one optical output device may comprise at least one current source that is voltage controlled, preferably based on an operational amplifier. An output circuit node of the at least one current source may be connected to the at least one optoelectronic device. An input circuit node of the at least one current source may be connected to at least one control signal and/or to an output circuit node of the at least one low pass filter unit in the case in which only one low pass filter unit is used or to an circuit output node of the at least one second low pass filter unit. In electrical engineering, a circuit node is any point on a circuit where the terminals of two or more circuit elements meet.

Abrupt changes of the current that flows via control lines may be reduced if a voltage control of the current source is used. In an MRI environment, abrupt current changes may lead to noise and artifacts. Therefore abrupt current changes have to be reduced as much as possible. The current source may be realized using at least one operational amplifier Op-Amp, preferably an Op-Amp that may have a high input impedance to minimize current flow.

The camera device and the optical output device may be integrated into the same housing. Thus the combined camera device/ optical output device may be an add-on device that is not integrated in the MRI scanner device, i.e. may be removed easily without screwing etc. There may be a separate power supply for the camera device and/or the optical output device and/or the illumination unit that is separate from a power supply of the MRI scanner device. This means that the camera device and/or the optical output device and/or the illumination unit may have their own common power supply. However, alternatively, integration of the camera device and/or of the optical output device into an MRI scanner is possible as well.

The illumination unit may also be integrated into the housing. The illumination unit may illuminate the field of view of the camera device in order to enable taking optical images.

The housing may comprise:

-   -   an electrical sending unit, preferably configured to send data         by changing the load on the power line,     -   an electrical receiving unit, preferably configured to evaluate         changes of power voltage of the power line, and     -   a transceiver circuitry connected to the electrical sending unit         and to the electrical receiving unit, preferably configured to         implement a frequency shift keying data transmission method or a         method comprising FSK .

Thus, the same electrical receiving unit may be used to send control signals/data to all three devices/units within the housing. The same electrical sending unit may be used by all three devices/units within the housing to confirm the control data and/or to send data which comprises values of the settings.

Alternatively, the power line communication between the housing and the control unit may be modified by placing the electrical sending unit that generates low changes in power voltage within the housing of the camera module/device. The receiving module that evaluates the current may also be placed within the housing. In this case, the control unit would have an electrical receiving unit that evaluates changes of power voltage. Moreover, the control unit would have an electrical sending unit that changes the load.

The housing may be mounted on a mounting frame, preferably pivotable. This may allow easy adaption to different application cases, for instance to persons having different body shapes and/or heights (e.g. children vs. adults) or to different areas of the body that may be in the field of view of the camera. The mounting frame may comprise a curved arm and a foot plate. The arm of the frame may be adapted to the head or wrest of child or of an adult. There may be a kit of arms or a kit of frames for different application cases. The head or wrest may be arranged between the housing and the foot plate. Additionally or alternatively the curvature of the arm and/or the whole frame may be adjusted to the shape of an MRI tube allowing a placement in a very narrow environment. Furthermore, the shape of the arm of the frame may be adjusted to additional coils used for MRI imaging, e.g. a head-coil.

The optical output device may comprise at least one optoelectronic signaling device that is configured to send the optical signals or at least a part of the optical signals to the subject. The optical output device may comprise at least three light emitting diodes that are placed preferably within a space that is smaller than 0.25 square centimeters. Thus color mixing of a wide variety of colors is possible. The human eye may recognize only one color that may be different from the colors of the different LEDs, e.g. orange although only red, green and blue LED are used.

At least one optoelectronic signaling device may be used for informative purposes of the subject. Thus, it would be easy to give feedback to the subject and/or to perform test series that require special signaling.

The optical output device may comprise at least one optoelectronic illumination unit/device that is configured to illuminate objects or parts of the subject in the field of view of the camera device, preferably with white light or with infrared light. White light LEDs may be used. The color of the illumination light may be different from the color of the signaling light to ease recognition of the signaling light by the subject/patient.

A second aspect relates to a camera module comprising any one of, any arbitrarily selected plurality of some or all of the following:

-   -   at least one optional first optoelectronic unit that is         configured to output signaling light, and/or     -   an optional camera device, and/or     -   and a second optoelectronic unit that is configured to         illuminate objects or parts of a subject in the field of view of         the optional camera device, and/or     -   an electrical sending unit, and/or     -   an electrical receiving unit, and/or     -   an optical sending unit.

The camera module may be configured to receive control data via the electrical receiving unit and to control the optional camera device and/or the optoelectronic units according to the received control data. Further, the camera module may be configured to acknowledge control data or to generate control data and send the control data via the electrical sending unit. Furthermore, the camera module may send image data generated in the camera device. The camera module may be configured to send these data via the optical sending unit. Alternatively, the camera module may send image data via the electrical sending unit. The optical sending unit may be omitted in this case.

Actually, another alternative may be that full optical fiber control of the camera device (and possibly of all other devices/units within the housing) is used and that electrical control is avoided. This may be done in the same way as the communication between control unit and receiving and sending unit with regard to control signals/data.

A third aspect relates to a control unit comprising any one of, any arbitrarily selected plurality of some or all of the following:

-   -   an optional splitting unit, and/or     -   a display unit, and/or     -   an input unit, and/or     -   an electrical sending unit, and/or     -   an electrical receiving unit, and/or     -   a radio transmitter unit that is connected to the optical         sending unit and to the optical receiving unit, and/or     -   an optical sending unit, and/or     -   an optical receiving unit.

The splitting unit may comprise at least a first port, a second port, a third port and a fourth port. The same features that are mentioned above for the splitting unit may be valid for the splitting unit of the control unit of the third aspect, e.g. four ports and/or the connection of these ports and/or the kind of data transmission between the ports.

The control unit may be configured to forward control data received at the second port to the electrical sending unit and to forward control data received at the electrical receiving unit to the second port. The control unit may be configured to show video data or image data received at the first port on the display unit. Furthermore the control unit may be configured to send control data that is entered using the input unit via the electrical sending unit.

For either of the camera module according to the second aspect and the control unit according to the third aspect MRI shielding/protected/compliance may be realized using the measures that are listed above, e.g. metal shielding, low currents, electrical filtering on transmission or power lines. The electrical and/or magnetic and/or electromagnetic interference with an MRI device (scanner) may be minimized for the optical output device and/or for the control unit. Both devices may be configured to operate within or nearby an MRI scanner device that generates a magnetic field that is greater than 0.8 T (Tesla) or greater than 1 T.

The camera module of the second aspect may comprise features of the optical output device according to any one of the embodiments mentioned above. Thus, the features, advantages and technical effects that are mentioned above are also valid for the optical output device of camera module of the second aspect. The control unit of the third aspect may comprise features of the control unit according to any one of the embodiments mentioned above. Thus, the features, advantages and technical effects that are mentioned above are also valid for the control unit of the third aspect.

A fourth aspect relates to a sending and receiving unit that may comprise:

-   -   an optical sending unit, and/or     -   an optical receiving unit, and/or     -   a radio frequency transceiver circuit that is connected to the         optical sending unit, and/or     -   a video signal or video data receiving unit that is connected to         the optical receiving unit, and/or     -   at least one interface unit, and/or     -   a forwarding unit that is connected to an output and/or to an         input of the transceiver unit and that is connected to an output         node of the video signal or video data receiving unit and that         is connected to at least one interface unit.

The forwarding unit may be configured to forward the video signal or the video data to the at least one interface unit and to forward control data that is received using the transceiver unit to the at least one interface unit. There may be a first interface unit for video data, for instance an HDMI (High Definition Multimedia Interface) interface. A second interface unit may be used for control data, for instance and USB (Universal Serial Bus) interface. However, it is also possible to use only one interface unit for both types of data.

The forwarding unit may optionally be configured to forward control data that is received using the interface unit to an input of the transceiver unit. Forwarding of control data may be bidirectional. Forwarding of image data/video data may be unidirectional. Thus, no video signal may be sent from sending and receiving unit back to control unit.

The sending and receiving unit may comprise a video output port that can be connected to an external device (e.g. frame grabber, monitor, etc.). This external device may not be included in the receiving and sending unit and/or within the system that is sold as one product. It may be expected to be chosen by the user on his own. The output port may be preferably an HDMI port or another appropriate port. Alternatively, the external device may be included into the system.

Only one (1) optical connection may form the connection between optical sending unit and optical receiving unit. An optical splitting unit or optical coupler member may be used.

Alternatively, i.e. instead of the at least one interface unit, a first data providing unit (for data input, control data, keyboard, instruction files, computer mouse, touchscreen, etc.) and a second data providing unit (for data output, video data, control (e.g. feedback) data, monitor, touchscreen, display, data files (video data, control data (e.g. feedback)) may be used within sending and receiving unit.

A HFBR-14xxZ transmitting unit made by Broadcom and a HFBR-24xxZ receiving unit made by Broadcom may be used. HFBR-24xxZ, especially HFBR-24x6Z, is specified for an electrical bandwidth of 125 MHz for −3 dB (Decibel). However, the radio frequency used within the radio frequency transceiver circuit should be selected for instance above 125 MHz, above 135 MHz or even above 145 MHz. Thus the transmission frequency that is uses for the transmission of control data is different from and exceeds the operation frequency or operation frequencies of the MRI device. The transmitting components and the receiving components or similar components may be appropriate for MRI devices although the components are used outside of the specification that is specified for these components.

The radio frequency transceiver circuit may use FSK (Frequency Shift Keying) and/or ASK (Amplitude Shift Keying). ADF 7020-x, 7020-1 made by Analog Devices or similar type may be used to implement radio frequency transceiver circuit.

The video signal or the video data may be transmitted using a bandwidth of up to 60 MHz from a camera module. Preferably the transmission of the video signal/data may be in the range of 0 Hz to 60 MHz or of 0 Hz to 50 MHz. or of 0 Hz to 70 MHz. This bandwidth may be specified by the camera circuits.

The transmission signal that is used for the transmission of the control signal or of the control data may use a transmission frequency in the range of 140 MHz to 180 MHz or a frequency in the range of 145 MHz to 152 MHz, for instance of 148 MHz. The control signal or the control data may be transmitted at the same time as the video signal or the video data is transmitted.

An optical transmission connection may be used that has a first end that is connected to the optical receiving unit and/or to the optical sending unit (for instance using a splitting unit/optical coupler element). The optical transmission connection may have a second end that may be located in the vicinity of an MRI device within a radius that is smaller/less than 10 meters or less than 5 meters.

The MRI device may generate a magnetic field in the range of 0.5 T (Tesla) to 3.5 T or in the range of 0.5 T to 7 T or in the range of 0.5 T to 10 T and an electro-magnetic field with a main frequency that is greater than 10 MHz.

The frequency of the transmission of the control signal or of the control data may be chosen to be different from a multiple of the main frequency of electromagnetic radiation of the MRI device preferably different by at least 1 MHz or at least 2 MHz. 1.5 T (Tesla) MRI scanners may use frequencies of about 64 MHz. 3 T MRI scanners may operate with radio frequencies of about 128 MHZ (for instance 127.734 MHz). To avoid any artifacts, frequencies above this value may be used, e.g. clearly above the 125 MHz electrical bandwidth of an optical receiver at the optical channel/connection, for instance at least above 110 percent of this value.

The sending and receiving unit may be configured to perform the proposed method for transmitting video signals and control signals via an optical transmission connection that is described below. Furthermore, the sending and receiving unit may comprise features of the sending and receiving unit of the system and its embodiments that are described above. Thus, the same technical effects may apply.

A fifth aspect that is not claimed yet relates to a method for transmitting video signals and control signals via an optical transmission connection. The method may comprise:

-   -   using a transmitter unit that comprises a transmitter of type         HFBR-14 or of a similar type,     -   using a receiver unit comprising a receiver of type HFBR-24,         especially HFBR-24x6Z, or of a similar type,     -   using an optical transmission connection arranged between the         transmitter unit and the receiver unit,     -   transmitting a video signal or video data comprising a bandwidth         of up to 60 MHz from a camera module,     -   transmitting a control signal or control data using a         transmission frequency in the range of 140 to 180 MHz ora         frequency of 148 MHz, wherein the control signal or the control         data may be or is transmitted at the same time as the video         signal or the video data is transmitted,     -   using the method in the vicinity of an MRI device within a         radius that is smaller or less than 10 meters or less than 5         meters.

The MRI device may generate a magnetic field in the range of 0.5 T (Tesla) to 3.5 T or in the range of 0.5 T to 7 T or in the range of 0.5 T to 10 T and/or an electro-magnetic field with a main frequency that is greater than 10 MHz. The frequency of the transmission of the control signal or of the control data is chosen or may be chosen to be different from a multiple of the main frequency of electromagnetic radiation of the MRI device, preferably different by at least 1 MHz or at least 2 MHz.

The following are examples of technologies that may be used in all aspects. Other technologies/fibers may be used as well:

-   -   820 nm wavelength technology, and/or     -   160 MBaud (Megabaud), range of 100 MBaud to 200 MBaud, and/or     -   100BASE-SX, and/or     -   multimode fiber (glass or plastic) or monomode fiber (glass or         plastic), and/or     -   including 50/125 micrometer (inner diameter, outer diameter)         fiber, or     -   62.5/125 micrometer fiber, or     -   100/140 micrometer fiber, or     -   200 micrometer fiber size.

The fiber length may be smaller or less than 25 meters or smaller/less than 10 meters but longer than 1 meter, longer than 3 meters or longer than 5 meters, especially the overall fiber length of both fiber connections that are mentioned above.

The method may comprise features that have been mentioned above. Therefore, the same technical effect may apply.

A sixth aspect relates to a transmission system for transmitting video signals and control signals via an optical transmission connection, comprising:

-   -   a first transmitter unit that comprises an optoelectronic output         element that converts an electrical signal into a light signal,         and/or     -   a receiver unit that comprises an optoelectronic input element         having a specified electrical bandwidth, wherein the         optoelectronic input element receives light and outputs an         electrical signal, and/or     -   an optical transmission connection arranged between the first         transmitter unit and the receiver unit, and/or     -   a camera module that is connected to the first transmitter unit,         and/or an optional second transmitter unit that comprises an         optoelectronic output element that converts an electrical signal         into a light signal, and/or     -   an optional optical coupling unit that is coupled between the         second transmitter unit and at least a segment of the optical         transmission connection, and/or     -   a radio frequency signal generation unit that generates a radio         frequency signal using a control signal or control data and that         has an output node which is connected to the first transmitter         unit or to the optional second transmitter unit.

The radio transmission frequency may be at least 10 percent of an upper limit of the specified bandwidth above the specified electrical bandwidth. The usage of a receiver unit that is operated outside its specified frequency allows a simple and cost efficient solution. Operation outside the specified frequency range is possible because the optical connection is comparably short. However, alternatively, the radio transmission frequency may be within the specified limit for the receiving unit.

The video signal may be separated from the control (data) signal using a low-pass filter. The control signal may be managed by an ADF7020 integrated circuit (IC) made by Analog Device or by comparable circuitries. The frequency for the transmission of the control signal may be located within a higher bandwidth than the video signal. Control data and video data/signal may be transmitted simultaneously.

The usage of only one receiving unit is possible even if both transmitting units send light of the same frequency at the same time. Alternatively, operation modes may be selected that prevent an operation of both transmitting units at the same time.

If operation of both transmission units at the same time is possible, an electrical filter unit, for instance a low pass filter unit, may be used on the side of the receiving unit to separate the received electrical video signal from the received electrical radio control signal. The electrical video signal may have frequencies in a lower part of the frequency band. The received radio control signal may have frequencies above the lower part of the frequency band. Furthermore, the radio signal may be modulated and/or coded to ease or enable the separation from the electrical video signal.

In the other direction, e.g. from the receiving and sending unit to the control unit, it is not necessary to send a video signal. This means that the sending unit has to transmit only the control signals that may have transmission frequencies within the radio frequency band.

The same technical effects that are mentioned above for the system and the other parts of the system may be valid for the transmission system as well.

The transmission system may be used within the vicinity of an MRI device, wherein at least the first transmitter unit and/or the optional second transmitter unit may be located within a radius from the MRI device that is less than 10 meters or less than 5 meters.

The same technical effects that are mentioned above for the system and the other parts of the system may be valid for the usage of the transmission system as well.

The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present disclosure provides many applicable concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the disclosed concepts, and do not limit the scope of the claims.

Moreover, same reference numerals refer to same technical features if not stated otherwise. As far as “may” is used in this application it means the possibility of doing so as well as the actual technical implementation. The present concepts of the present disclosure will be described with respect to preferred embodiments below in a more specific context namely a system for communicating with a subject during magnetic resonance imaging (MRI). The disclosed concepts may also be applied, however, to other situations and/or arrangements as well, for instance for communicating with a subject during other kinds of imaging, especial imaging in a medical context. Furthermore, the proposed system may be used to communicate with subjects that are treated with medical devices, for instance with radiology devices or with other devices.

The foregoing has outlined rather broadly the features and technical advantages of embodiments of the present disclosure. Additional features and advantages of embodiments of the present disclosure will be described hereinafter. These features may be the subject-matter of dependent claims. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or processes for realizing concepts which have the same or similar purposes as the concepts specifically discussed herein. It should also be recognized by those skilled in the art that equivalent constructions do not depart from the spirit and scope of the disclosure, such as defined in the appended claims.

For a more complete understanding of the presently disclosed concepts and the advantages thereof, reference is now made to the following description in conjunction with the accompanying drawings. The drawings are not drawn to scale. In the drawings the following is shown in:

FIG. 1 an overview over an MRI camera system,

FIG. 2 the general configuration of the video part and of the control part of the MRI camera system,

FIG. 3 a frame head used for carrying parts of the system including a multicolor optical signal devices,

FIG. 4 a frame of a holder device,

FIG. 5 a control device for the RGB LEDs,

FIG. 6 a video signal transmission part and a control signal transmission part of the MRI camera system, and

FIG. 7 a splitting unit that is part of a control unit.

FIG. 1 illustrates an overview over an MRI (Magnetic Resonance Imaging) camera system 100. System 100 comprises:

-   -   a camera device 110, for instance generating an analog signal,         for instance PAL (Phase Alternating Line) or NTSC (National         Television Systems Committee, US) or a digital signal, for         instance 720×576 pixel (PAL) or 720×480 pixel (NTSC). It is         possible to generate monochrome or color signals within camera         device 110.     -   an optical output device 120, and     -   a control unit 130 that may comprise a display or a monitor Mon         and an input device In, for instance as part of a touch screen.

Camera device 110, Cam and optical output device 120 may be separate devices. However, in the preferred embodiment camera device 110, Cam and optical output device 120 are arranged within the same housing and it may be said that the optical output device 120 is integrated within the camera device 110.

Camera device 110, Cam and optical output device 120 may be arranged within the interior space 194 of a MRI device 192 (scanner), i.e. within the inner tube or gantry that is surrounded by big coils that generate a high magnetic field during image acquisition using magnetic resonance tomography (MRT). However, camera device 110 generates images/pictures or video data using optical sensors, for instance CCD (Charges Coupled Device) or CMOS (Complementary “metal” oxide semiconductor) sensors arranged in a matrix, i.e. in lines and columns. Camera device 110, Cam and optical output device 120 have to fulfill requirements with regard to MRI shielding and compliance, i.e. they should work properly within high magnetic fields and they should not disturb the MRT.

Camera device 110, Cam and optical output device 120 may be removable or removably placed within MRI device 192. A connection segment 170 may connect control unit 130 to camera device 110 and to optical output device 120. Connection segment 170 may comprise flexible cables that form a first connection 172 between control unit 130 and camera device 110 and a second connection 174 between control unit 130 and optical output device 124. However, both connections 172 and 174 may end at camera device 110 if optical output device 120 is integrated within camera device 110.

Optical output device 120 may comprise an illumination unit 122 and a signaling unit 124. Illumination unit 122 may comprise light sources, for instance for white light, or other radiation sources (for instance IR (Infrared) radiation) that radiate electromagnetic radiation II1 into the field of view of the camera device 110 enabling recording of optical images thereby. It is possible to take images/pictures/video streams of the face of the person and/or to take a video stream of the chest, for instance to determine the breathing cycle.

Signaling unit 124 may comprise a light source that generates light that is used for signaling purposes. The light generated by signaling unit 124 may also be directed mainly to the field of view (FOV) of the camera of camera device 110, see signaling light Si1. This may be the case, for instance if the face of the patient is within the focus of the camera of camera device 110. Alternatively, light generated by signaling unit 124 may be directed mainly to a region that is not within the focus of the camera, see signaling light Si2, for instance if the chest of the patient or subject is within the focus but the signaling light has to be seen by the eyes of the patient. One example for the arrangement of camera device 110, illumination unit 122 and a signaling unit 124 is shown in FIG. 3 that is described below.

Control unit 130 may comprise an output unit Mon, for instance a screen, display, a monitor or a touchscreen, for showing the video stream that is generated by camera device 110. Furthermore, control unit 130 may comprise an input device “In” that is used to enter control instructions and/or control data, for instance switching on/off illumination light, switching on/off signaling light, for instance using different colors, selecting video mode of camera (PAL, NTSC), etc. Input device In may also be a touchscreen or other input device.

System 100 may be a system which comprises a recording camera device 110 designed for diagnostics and testing in MRI scanners 192. The use of the camera device 110 may increase the safety of the test subjects or of patients and the effectiveness of MR (magnetic resonance) tests or of MRT. It may allow one to see the patient or subject during MRI and fMRI (functional MRI) tests/imaging and may provide feedback on their activity.

The system may include or comprise a camera device 110, an output device Mon (monitor) and a lighting system 120 mounted for instance in the camera device 110.

The camera of the camera device 110 may allow watching the face or other parts of the patient's or subject's body during the MRI scanning procedure. The camera device 110 may provide feedback about the activity of the patient. The camera device 110 may also allow the patient to be observed by the investigator or, in the case of procedures done with children, by the parents.

An output device Mon (monitor), for instance a touch screen, may be used for viewing the image and setting the lighting parameters. The output device Mon and/or the control device 130 may be mounted on the MRI scanner's 192 housing. The touch screen or another input device “In” may allow the examiner or investigator to adjust some of or all settings of the camera that may be placed inside of the gantry, i.e. within the tube, without leaving the MRI scanning room, making their work easier and more convenient.

Lights may be mounted within the camera housing, see FIG. 3, reference numeral 304. The lights may be operated with the input device “In”, for instance with a touch screen. The lights may allow additional lighting of the face of the patient, for instance using white light. Infrared lighting may be useful in case of studies requiring darkness. Multicolored light signals may enable communication and may significantly simplify conducting a variety of MRI or fMRI studies or may be used for other purposes.

FIG. 2 illustrates the general configuration of the video part and of the control part of a MRI camera system 200 that may comprise more devices compared to system 100. System 200 may comprise:

-   -   a camera device 210 that may corresponds to camera device 110         and that may comprise the same features that are described         above, and/or     -   an optical output device 220 that may correspond to optical         output device 120 and that may comprise the same features that         are described above, and/or     -   a control unit 230 (display, monitor, touch screen) that may         correspond to control unit 130 and that may have the same         features that are described above, and/or     -   a power supply device 240 that may generate the electrical power         for control unit 230 and/or for camera device 210 and/or for         optical output unit 210, and/or     -   an optional sending and receiving unit 250, and/or     -   an optional computing device 260, for instance a computer,         preferably a work station computer.

Sending and receiving unit 250 may be a separate unit or may be part of computing device 260, i.e. using the same internal power supply unit, being arranged within the same housing etc.

There may be the following connections within system 200:

-   -   a connection segment 270 between control unit 230 and optical         output device/camera device 220. Connection segment 270 may         correspond to connection segment 170 (see features mentioned         above) and may comprise an optical connection 272 (may         correspond to 172) and a power line connection 274 (may         correspond to 174), for instance via an electrical cable or         line, and/or     -   a power line connection 280 that delivers electrical current and         electrical voltage from power supply 240 to control unit 230,         for instance an electrical conductive cable or line, and/or     -   an optional optical connection 284 between control unit 230 and         sending and receiving unit 250, and/or     -   an optional connection 286 or a wireless connection between         sending and receiving unit 250 and computer 260, for instance a         USB (Universal Serial Bus) connection.

A splitting unit 600 may be comprised within control unit 230. The components of the splitting unit 600 are described below in connection with the description of FIG. 7 in more detail. Splitting unit 600 may play a central part in forwarding data within system 200.

An MRI device room 290 may comprise: MRI device 192, optical output unit 210 (arranged within interior space that is surrounded by MRI device 192), camera device 220 (arranged within interior space that is surrounded by MRI device 192) and power supply device 240. Optical output unit 210, camera device 220 and power supply device 240 may be MRI shielded/protected in order to guarantee proper operation during MRT imaging process and in order to prevent artefacts within the MRT image due to the operation of these devices.

Alternatively, power supply device 240 may be located outside MRI device room 290. For safety reasons the power supply device 240 may be able to detect a magnetic field strength above 20 mT (milli Tesla). After the detection of a high density magnetic field the power supply device 240 may cut off power supply to the system and may indicate danger, for instance by emitting red light. Furthermore, all power lines may comprise additional filtering.

A wall 292 separates MRI device room 290 from a control room 294. Wall 292 may have special shielding, for instance magnetic shielding or EMC (Electro Magnetic Compatibility). Alternatively or additionally, wall 292 may have an appropriate thickness and/or material, for instance armored concrete. Control room 294 comprises sending and receiving unit 250 and computing device 260 and/or optionally power supply device 240. This also means that sending and receiving unit 250 and computing device 260 and/or power supply device 240 in control room 294 do not have to fulfill special requirements with regard to MRI shielding/protection.

Thus a communication between a touch screen unit or control unit 230, a receiver unit (sending and receiving unit 250) and a camera device 210 is described. Control unit 230 and sending and receiving unit 250 may allow controlling some or all camera setting options of the camera within camera device 210 and receiving video signals. All control signals and/or video signals may pass through touch screen unit, i.e. through control unit 230. Thus, control and monitoring of image/video data may be possible from control unit 230 and from computing device 260. Alternatively, it may only be possible to enter control data using control unit 230 or computing device 260. Furthermore, it is possible to operate the light sources of optical output device 120, 220 using control unit 230 and/or computing device 260, for instance for communication with the person or patient who is examined within MRI device room 290, i.e. sending signals to this person.

FIG. 3 illustrates a frame head 300 for carrying parts of system 100 or 200 including for instance only one multicolor optical signal device (for instance RGB (Red Green Blue) LED (Light Emitting Diode), at least one multicolor optical signal device, only one signal device (for instance red LED, green LED or blue LED) or a plurality of signal devices (for instance several LEDs of a different or of the same color).

Frame head 300 may comprise:

-   -   an outer ring 302,     -   a housing 304,     -   an optional operating element 306,     -   a camera 308 of camera device 110, 210,     -   at least one illuminating device 310, i.e. one, two, three, four         or more than four, and     -   only one or at least one signaling device 320, i.e. one, two,         three, four or more than four.

Outer ring 302 may have a circular or elliptical shape. Outer ring 302 may be used to mount and hold housing 304 relative to an arm of a frame that comprises frame head 300, see also FIG. 4.

Housing 304 may comprise camera device 110, 210 and optical output unit 120, 220. Housing 304 may have a disc shape or a disc like shape. There may be only a narrow gap between outer ring 302 and housing 304 enabling a good protection of the housing, especially of the breakable camera 308 against mechanical impact.

Operating element 306 may be mounted to housing 304, i.e. if operating element 306 is rotated or turned, housing 304 pivots or rotates around an axis A with regard to outer ring 302. Housing 304 may be tilted relative to outer ring 302, see FIG. 4. This movement may allow proper positioning of camera 308 and/or of illuminating lights and/or of signaling light(s). Operating element 306 may be an engrailed disc in order to ease operation thereof.

Camera 308 may be part of camera device 110, 210. Camera 308 may allow use of several interchangeable photographic objectives or lenses of different angels of view and/or different focal lengths. Alternatively only one lens may be used. An aperture of camera 308 may be located on a central axis of housing 304 that may be arranged coaxially with outer ring 302 if both parts are within the same plane.

In the example, there are four illuminating devices 310 that may be part of illuminating unit 122 or of a corresponding illuminating unit of optical output device 220. Preferably, optoelectronic devices are used as illuminating devices 310, for instance LEDs. It is possible to use LEDs that radiate white light and/or LEDs that emit IR (infrared) radiation. Alternatively, other types of illuminating devices may be used, for instance lamps with or without a filament.

Four illuminating LED modules 310 may be used in the example that is shown in FIG. 3. Each illuminating LED module may comprise or contain one white LED and one IR LED. Alternatively, only one of these LEDs may be used in each module, for instance only white LEDs, only IR LEDs or some module(s) only with white LED(s) and other module(s) only with IR LED(s).

In the example shown in FIG. 3 only one signaling device 320 is used. Signaling device 320 may be part of signaling unit 124 or of a corresponding signaling unit of optical output device 220. Preferably, optoelectronic devices are used as illuminating devices 320, for instance LEDs. It is possible to use LEDs that radiate white light, colored light of a single wavelength or narrow wavelength band (less than for instance 50 nm), or that radiate multicolored light (for instance two, three or more than three small narrow wavelength band, each less than for instance 50 nm). RGB LEDs or multicolor LEDs may be used to radiate multicolor light, i.e. a mix of several colors. Alternatively, other types of signaling devices may be used, for instance lamps with or without a filament or rotating disks carrying areas of different colors. Only one color area may be visible through an aperture if the disc is in its corresponding angular position. The rotating disk may be illuminated directly or indirectly.

The RGB LEDs may be driven by a PWM (Pulse Width Modulated) controlled current source, preferably by a voltage controlled current source. This is explained in more detail with regard to FIG. 5 below. Alternatively, it is possible to use digital analog converters (DAC) of a microprocessor or separate DACs to control the current source. Other examples may comprise more than one RGB LED module or single LEDs of different colors.

In the example shown in FIG. 3, there is the following arrangement of elements:

-   -   the aperture of camera 308 of camera device 110, 210 is arranged         centrally within housing 304 wherein a center point CP is         arranged in the center of the aperture/lens of the camera 308         (optical axis),     -   illuminating devices 310 are arranged at a radius R1 from center         point CP and neighboring illuminating devices 310 may have the         same distance especially the same angular distance. This may         also be valid if less than four or more than four illumination         devices are used.     -   signaling device 320 is arranged at a radius R2 from center         point CP. Radius R2 may be greater than radius R1, for instance         by at least 10 percent of radius R1. Furthermore, the radiation         characteristic of signaling device 320 that is comprised in         signaling unit 124 or a corresponding unit of optical output         device 220 may be adapted to radiate away from illuminating         devices 310 in order to ease recognition of the signaling by the         subject or patient.

Housing 304 may comprise further parts, for instance screws for holding two or more parts of housing 304 together, or parts that are placed on the rear side that is not visible in FIG. 3.

FIG. 4 illustrates a frame 400 that forms a holder device for housing 304. Frame 400 comprises:

-   -   frame head 300     -   an arm 402, and     -   a foot plate 404 that forms a base.

A connection port 406 may be arranged onto housing 304. Connection port 406 may be used to connect optical connection 172 or 272 to housing 304. Furthermore, connection port 406 may be used to connect power cable 174 or 274 to housing 304. Optical connection 172, 272 and power connection 174,274 may be combined into one physical cable. Connection port 406 may then comprise optical connection and electrical connection. Power cable 174, 274 and optical connection 172, 272 may be connected to housing 304 in various ways, for instance using arm 402 or parts of arm 402 for guiding the cable 174, 274.

An inner tube of MRI device 192 is also shown in FIG. 4. Furthermore, the head 410 of a person or patient is shown. The inner tube surrounds interior space 194. Head 410 is placed within interior space 194. Arm 402 of frame 400 may be curved and may be adapted to the shape of the head 410 and/or to the shape of inner tube of MRI device 192. Head 410 may be placed on foot plate 404 of frame 400 thereby also fixing frame 400 to a bed on which the patient lies. There may be no further mounting means for mounting frame 400 to the bed. Alternatively, further mounting/fixation means may be used, for instance clamping devices. Additional components of frame 400 should not be ferromagnetic nor conductive.

Signaling device 320 may be located nearer to the eyes of the patient than illuminating devices 310 in order to ease recognition of the signaling. The nose of the patient is nearer to the head 300 of frame 400 than the back of head 410 of the patient, i.e. the back of head 410 rests on foot plate 404. Foot plate 410 of frame 400 may be upholstered. The distance between head 300 of frame 400 and foot plate 404 may be in the range of 30 cm (centimeters) to 50 cm.

FIG. 5 illustrates a control circuitry 500 for the RGB LED module 320. Control circuitry 500 may be used to control signaling device 320 and may comprise:

-   -   a processor 502,     -   an optional PWM (pulse width modulation) circuit 504,     -   a low pass filter unit 506,     -   a current source circuit 508,     -   and signaling device 320.

A serial connection of only one PWM circuit 504, of only one low pass filter unit 506, of only one current source circuit 508 and of only one LED may be used to control this LED. Thus, the number of PWM circuits 504, of low pass filter units 506 and of current source circuits 508 depends on the numbers of LEDs that have to be controlled. Different PWM duty cycles may be used for each one of the LEDs. In the example that is shown in FIG. 5 three LEDs are comprised within signaling device 320. However, in the following only one serial connection of only one PWM circuit 504, of only one low pass filter unit 506, of only one current source circuit 508 are described for the red R LED of signaling device 320. There are corresponding serial connections for the green G LED and for the blue B LED of signaling device 320. Thus, there may be three independent PWM circuits 504, three independent low pass filter units 506 and three current source circuits 508.

There may be the following connections:

-   -   an electrical connection 520 between an output of the PWM         circuit 504 and an input of low pass filter unit 506,     -   an electrical connection 522 between an output of low pass         filter unit 506 and an input of current source circuit 506, and     -   an electrical connection 524 between an output of current source         circuit 508 and an input port 512 of the red R LED on signaling         device 320.

Microprocessor 502, PWM circuit(s) 504 and low pass filter unit(s) may be arranged on a first PCB (printed circuit board). Current source circuit(s) 508 and signaling device 320 may be arranged on a second PCB. Connection 520 may be made as short as possible in order to reduce electromagnetic radiation therefrom. Connection 520 may be shorter than 20 mm (millimeters) or shorter than 10 mm or shorter than 5 mm or even shorter than 3 mm, for instance about 2,1 mm. Connection 522 between the first PCB and the second PCB may also be as short as possible, for instance less than 20 mm, less than 10 mm or less than 7 mm, for instance 6 mm or about 6 mm. However, length of connection 524 also should be as short as possible, however it is additionally protected using low pass filter unit 506.

Processor 502 may be a standalone processor or a processor that is part of a microcontroller. The processor may execute instructions of a program. Alternatively, a state machine (FPGA (Field Programmable Gate Array), PLD (Programmable Logic Device), CPLD (Complex PLD), etc.) without a processor that executes instructions of a program may be used.

PWM circuit 504 may realize a periodical on/off switching of a signal. The ratio between on time (duty cycle) and off time may be selected appropriately depending on a data value that specifies the brightness of the red R LED. By using a PWM signal, it is possible to use only two voltage levels which is appropriate for signal transmission in complex environments (for instance with strong electromagnetic interferences). The transmission of only two voltage levels or electrical potentials is more reliable than transmission of a voltage value that may be within a continuous range. Furthermore, switching mode of transistors requires lower power than continuous operation.

The PWM signal may be generated from analog signals (for instance using a raising signal (saw tooth signal or triangle signal) and a comparator. Alternatively, the PWM signal may be generated from digital signals. It may be possible to use DAC (Digital to Analog Converter) units of a microcontroller to control LEDs directly, i.e. without using separate PWM circuits. However, these units may be used already for the illumination device 324. Thus, separate PWM circuits may be used for signaling device 320.

The frequency of the PWM may have various values, e.g. to be in the range of 80 to 150 Hertz. The PWM signal is filtered with analogue filters 506 that are adjusted to the PWM frequency. Thus LEDs are driven with a continuous electrical signal that does not introduce artifacts to MRI environment. Changes in PWM parameters will be reflected in the brightness of LEDs.

Low pass filter unit 506 may comprise only one low pass filter to prevent abrupt changes of current flow which may lead to MRI artefacts. Alternatively, low pass filter unit 506 may comprise more than one filter unit, i.e. two filter units or more than two filter units that are connected serially. Low pass filter unit 506 may comprise a first low pass filter unit 506 a and a second low pass filter unit 506b that receives the output signals of the first low pass filter unit 506 a. The cut off frequency of the first low pass filter unit 506, for instance 159 Hertz may be higher than the cutoff frequency of the second low pass filter unit 506, for instance 146 Hertz.

Usually, low pass filtering may not be used for controlling LEDs because color of radiation and degree of efficiency of the LED may depend on the amount of current. Furthermore, the light intensity of the LED depends in a strongly nonlinear way on operation current. However, reducing MRI interference may be a reason to use a low pass filter unit, especially in combination with a current source that is voltage controlled, i.e. there are already comparably low currents.

Current source circuit 508 may be based on an OP-Amp (Operational Amplifier). Preferably, a voltage controlled amplifier may be used in order to reduce MRI artefacts because only small currents are necessary in order to perform control of the current source circuit 508. Current source circuit 508 outputs a current that depends on the input voltage. Voltage controlled current sources are known for instance from Tietze U. and Schenk, Ch., “Halbleiter-Schaltungstechnik” 10th edition, Springer, 1993, page 367 to page 378.

Signaling device 320 may comprise or consist of a multi LED 512 that is within an integrated circuit (IC). Signaling device 320 may comprise an input port 512 for each LED of the multi LED 514, i.e. there may be three input ports 512. At least one further port may be used for power supply.

Processor 502 may be a processor that is appropriate for operation within an MRI device 192, i.e. a low power processor or a low power microprocessor or a low power microcontroller. Additionally or alternatively, processor 502 may be shielded using metal.

Thus, filter units 506 and current source circuits 508 may be implemented in order to avoid abrupt changes on current flow that may lead to MRI artifacts. Filter units 506 may be located in a very short distance to PWM outputs to avoid longer lines that may cause MRI artifacts. Current source circuit 508 may be voltage-controlled, based on an Op-Amp that has high input impedance to minimize current flow. Brass shielded electronic circuits may be used for MRI protection.

In general the following measures may be used for MRI protection:

-   -   current-source controlled LEDs,     -   (micro-)processor and/or control circuits and/or transmission         circuits and/or camera matrix may be shielded, especially metal         shielded, e.g. brass or copper shielded,     -   low-power (micro-)processors may be used for low current flows,     -   data transmission may be realized through optical fibers or         electric control lines with additional resistors. The resistors         may be combined with capacitance of the circuits in order to         create RC (Resistor Capacitance) filters which may be         empirically adjusted or which may be adjusted based on         simulations.     -   filtering on power lines may be used.

FIG. 6 illustrates a video signal transmission part and a control signal transmission part of the MRI camera system 200. Video signal transmission is illustrated by continuous lines. Control signal transmission is illustrated by dashed lines.

For the video output the following applies:

-   -   the video signal is created in camera device 210 and is sent         from optical sending unit S1 through optical connection 272, for         instance an optical fiber, to control unit 230 (touch screen         unit), especially to a port P1 of splitting unit 600,     -   within splitting unit 600 of control unit 230 the video signal         is split into two signal paths SP1 and SP2. Signal path SP1 is         connected with a port P2 of splitting unit 600. Port P2 is         connected with optical connection 284 that guides optical waves         to an optical receiver R2 within sending and receiving unit 250.         Signal path SP2 is connected with a port P4 of splitting unit         600. Port P4 is connected with an optical receiver unit R3.     -   control unit 250 processes the video signal and allows to view         the image on output device Mon,     -   the video signal goes through optical connection 284 (fiber) to         sending and receiving unit 250 that is located in         technical/control room 294,     -   the video signal is processed in sending and receiving unit 250         and is sent to computing device 260 (PC (Personal Computer)) or         to another device (frame grabber, monitor, display) that may         comprise a recording device and/or a viewing device.

Control signals (see dashed lines) can be managed either by control unit 230, for instance using a touch screen, or by sending and receiving unit 250 and/or computing device 260. If control is performed by sending and receiving unit 250 and/or computing device 260 the control signal goes through control unit 230. This way camera device 210 and/or optical output device 220 always receive control signals from control unit 230, for instance from touch screen unit.

Between sending and receiving unit 250 and control unit 230 the control signal is transmitted from an optical sending unit S2 through optical connection 284 (fiber) (the same connection 284 may transfer video signals) to port P2 of splitting unit 600. Within splitting unit 600, there is a signal path SP3 from port P2 to port P4 of the splitting unit. Port P4 is connected with optical receiving unit R3 of control unit 230. Between control unit 230 and sending and receiving unit 250 the control signal is transmitted from a sending unit S3 that is connected with a port P3 of the splitting unit through a signal path SP4 within splitting unit 600 to port P2 of the splitting unit and further via optical connection 284. The signal paths Sp1 to Sp4 are shown in more detail in FIG. 7.

Between control unit 230 (touch screen unit) and camera device 210 and/or optical output device 220 control signals are transmitted through power line connection 274. An electrical sending unit S4 of control unit 230 is connected to power line connection 274 as well as an electrical receiving unit R4 of control unit 230. Furthermore, an electrical sending unit S5 of combined camera device 210 and/or optical output device 220 is connected to power line connection 274 as well as an electrical receiving unit R5 of combined camera device 210 and/or optical output device 220. It is possible to use separate sending units and receiving units for camera device 210 and for optical output device 220, all of them connected to power line connection 274.

The control signals may be unidirectional from control unit 230 to combined camera device 210 and/or optical output device 220, i.e. on power line connection 274. Alternatively control signals may be bidirectional on power line connection 274, for instance using acknowledgement commands and/or sending status data to control unit 230. Control signals may be unidirectional from sending and receiving unit 250 and/or computing device 260 to control unit 230 and then further to combined camera device 210 and/or optical output device 220. Alternatively control signals may be bidirectionally transmitted on optical connection 284, for instance for acknowledgment or for sending status data.

Splitting unit 600 may be an integral part of control unit 230, i.e. contained within the same housing, or splitting unit 600 may be separate from control unit 230. Alternatively, splitting unit 600 may be a separate part from control unit 230.

Transceiver units may be coupled to respective pairs of sending units and receiving units, e.g.:

-   -   a transceiver unit TR2 to sending unit S2 and to receiving unit         R2,     -   a transceiver unit TR3 to sending unit S3 and to receiving unit         R3,     -   a transceiver unit TR4 to sending unit S4 and to receiving unit         R4, and     -   a transceiver unit TR5 to sending unit S5 and to receiving unit         R5.

Communication of control signals over power line connection 274

Camera device 210 and/or optical output unit 220 may be controlled over power supply, i.e. via power line connection 274 by the control unit 230 (touch screen unit). This may be a bidirectional communication. The following rules may apply:

-   -   One of the devices (control unit 230/Touch Screen Unit) is the         master unit and the other one (camera device 210/optical output         device 220) is the subordinated unit (slave).     -   the master may provide voltage signal for powering and         communication of the slave via the power line connection 274,     -   the voltage signal of the master may comprise of constant         voltage (DC, direct current/voltage) component for power supply         and an alternating voltage component for communication of         control signals,     -   the slave may record changes of the alternating voltage         component to read the information of the control signal,     -   the slave may control electric load of the power line which         influences current flow through the line,     -   the master may measure the current flow on the power line which         allows to read control information sent by the slave.

However, other modes of communication of control signals on power line connection may be used as well. It is also possible to transmit control signals via optical connection 272 between combined camera device 210 and/or optical output device 220 and control unit 230. There may be only one receiving unit and only one sending unit on the side of combined camera device 210 and/or optical output device 220. Control data is collected and distributed appropriately between camera device 210 and optical output device 220. However, it is also possible to use separate receiving units and sending units for camera device 210 and optical output device 220 for control signaling on power line connection 274. An addressing method may be used in this case. A further alternative is to use two separate power line connections.

A detection circuit of the current within the master unit or of the voltage within the slave unit may be preceded by RC (Resistor Capacitor) filtering which may exclude the DC (direct current/voltage) value from the line.

In order to minimize artifacts, noise and power consumption, the coding of the signal may be designed so that the mean value of the alternating voltage and current component is equal to 0. The bit rate of the communication may be in the range of 0.1 bit/ms to 10 bits/ms, for instance 1 bit/1 ms (millisecond).

Each control command may comprise or consist of:

-   -   command information,     -   frame format information,     -   cyclic redundancy check CRC, and     -   forward error correction FEC.

CODING:

Frequency-Shift Keying (FSK) may be used on power line connection 274 to meet the requirements. This coding may utilize discrete frequency changes of carrier signal. Frequency lower than nominal frequency may be called ‘0’ and frequency higher than nominal frequency may be ‘1’. There may be a third state, ‘s’, that relates to no signal and marks the beginning of the frame, and that is also used on the transmission line while no information is transferred. The third state may be a state with simply no changes of voltage and/or current flow—thus a constant power supply voltage and/or constant load may be there.

Each single information time slot may be marked by at least 5 periods of ‘0’ signal or by 10 periods of ‘1’ signal.

The shortest frame may be defined as: s010xxxxxxxx(and may comprise or consist of:

-   -   at least 12 slots, consecutively:         -   ‘s’ marks the beginning of the frame,         -   ‘010’ allows for preparation of the receiver, i.e. defining             width of each symbol, other preambles may be used as well;         -   8 or more bits with the command information, for instance in             LSB (least significant bit) first sequence.

The shortest frame may take 18 time slots. The shortest frame may be elongated by adding more bits with information, ex. up to 256 bits (i.e. 32 B (Byte)).

Command information may be followed by 1 B (Byte) of check sum.

The shortest frame may take no longer than 20 ms (milliseconds), thus 1 time slot should take 1.111 ms (milliseconds). This may require that the frequency of ‘0’ is at least 4.5 kHz (Kilohertz) (f0) and the frequency of ‘1’ may be 9 kHz (f1).

To meet requirements of implementing the coding on microprocessor with MCU frequency of for instance 32 MHz (MCLK), the following parameters may be set:

-   -   f1=10 kHz,     -   f0=5 kHz (or higher, but lower than f1),     -   tslot=1 ms, and     -   shortest frame period of 18 ms.

However, other clock frequencies may also be used. If other clock frequencies are used there may be corresponding changes with regard to the overall timing.

Sampling frequency (Fsmp) of Analog-to-Digital Converter (ADC) should or may not be lower than 2×10 kHz. However to allow oversampling sampling frequency Fsmp may be equal to 40 kHz, which may fit the requirements of the microprocessor or of other computing devices.

Communication of video signals and of control signals over optical fiber

To provide best performance and easy to use setup in MRI (Magnetic Resonance Imaging) environment, sending and receiving unit 250 should or may send and receive control signals to/from control unit 230 (for instance comprising a touch screen) through optical connection 284 (fiber), i.e. passing through an electromagnetic waveguide for light. To avoid using multiple optical fibers, a single optical fiber may be used for either transmitting video signal and control signals. Splitting unit 600 located within control unit 230 (touch screen) may combine signals coming from video output and control signals. Optical signals may be transmitted through transmission channels that operate using for instance transmitters HFBR-1414MZ of Broadcom® and receivers HFBR-2416TZ Broadcom®. However, other devices of Broadcom° or of other companies may also be used. These electronic circuits allow a nominal bandwidth of up to 125 MHz (Megahertz). Video signals may use a bandwidth of up to 60 MHz (Megahertz). This may leave higher frequencies unoccupied and suitable to use them for control signal transmission. In order to simplify design, it was proposed that wide bandwidth radio transmitters or transceivers (for example using frequencies of 80 MHz and higher, ex. ADF7020-1 BCPZ of Analog Devices®, or corresponding devices of other companies) may be used to control transmission channels for control signals and/or for video signals.

It should be noted that MRI scanners may use radio frequencies for their operation and this may lead to noise during the operation of the system. 1.5 T (Tesla) MRI scanners may use frequencies of about 64 MHz while 3 T MRI scanners may operate with radio frequencies of about 128 MHZ (for instance 127.734 MHz).

To avoid any artifacts, it could be necessary to use frequencies above this value, so clearly over the 125 MHz bandwidth of optical channels. It may be highly recommended to avoid of using any signal near MRI work frequency and signals which multiples are near MRI work frequency.

Radio frequency transmitters however have the advantage of being able to operate at low signal-to-noise ratio and have very high dynamic range. We verified that the system consisting of radio transmitter and optical channels may work even without matching to transmission line's characteristic, i.e. electrical and/or optical, provided that the system consists of separate receive RX and transmit TX lines of radio transmitter (transceiver) and that radio transceiver is voltage controlled. The transceiver circuits may be voltage controlled by a microprocessor, for instance using TTL (Transistor-Transistor Logic) technology. Current control may be used only for some components of the system, especially for some other components than the transceiver, in order to control current changes more precisely. Minimal dynamics of transmission line must be about 80 dB (Decibel). Radio transceivers may allow to couple analog video signal with digital control signals in one fiber without both signals degradation. Alternatively, a multi-fiber connection may be used. However more fibers may complicate the connection between control unit 130, 230 (Touch Screen Unit) and receiver unit 250.

FIG. 7 illustrates splitting unit 600 in more detail. Splitting unit 600 may comprise:

-   -   a splitting member 702 (coupler),     -   a splitting member 704 (coupler),     -   internal optical connection OC1, and     -   internal optical connection OC2.

Splitting member 702 (coupler) may be a 50% (percent)/50% split ratio coupler. Other ratios are also possible. Splitting member 702 may have four ports X1 to X4. Ports X1 and X2 are on one end of splitting member 702 and ports X3, X4 are on the other end of splitting member 702. Splitting member 702 may be a bidirectional coupler, i.e. either end may be used as an input and the respective other end is the output. An input signal at one port (for instance port X1) at one end is transmitted to the ports (X3, X4) at the other ends, whereby the optical power is reduced to 50 percent on both output ports if compared with the power on the input port.

Splitting member 704 (coupler) may also be a 50% / 50% split ratio coupler. Other ratios are also possible. Splitting member 704 may have four ports Y1 to Y4. Ports Y1 and Y2 are on one end of splitting member 704 and ports Y3, Y4 are on the other end of splitting member 704. Splitting member 704 may be a bidirectional coupler, i.e. either end may be used as an input and the respective other end is the output. An input signal at one port (for instance port Y1) at one end is transmitted to the ports (Y3, Y4) at the other ends, whereby the optical power is reduced to 50 percent on both output ports if compared with the power on the input port.

Receiving and sending unit 250 may comprise a further splitting member 706, for instance a 90%/10% split ratio coupler. Other ratios are also possible for instance 75%/25%. Splitting member 706 may have three ports Z1, Z3 and Z4. Port Z1 is on one end of splitting member 706 and ports Z3, Z4 are on the other end of splitting member 702. Splitting member 702 may be a bidirectional coupler, i.e. either end may be used as an input and the respective other end is the output. An input signal at one port (for instance port Z1) on one end is transmitted to the ports (Z3, Z4) at the other ends, whereby the optical power is reduced to 90 percent on one output port Z4 and to 10 percent on the other output port Z3 if compared with the power on the input port. Port Z4 may forward the signal to optical receiver unit R2 of the receiving and sending unit 250. Port Z3 is connected to optical sending unit S2 and transmits the signal. There may be no signal power loss in this direction, i.e. from port Z4 to port Z1 and/or from port Z3 to port Z1.

All splitting members 702 to 706 may be splitting members of THORLABS, see www.thorlabs.com, for instance 50:50 wideband fiber coupler or 90:10 wideband coupler. However, splitting members produced by other companies may also be used.

Internal optical connection OC1 may be coupled to port X4 of splitting member 702 and to port Y1 of splitting member 704. Internal optical connection OC2 may be coupled to port X3 of splitting member 702 and to port Y3 of splitting member 704.

Port P1 of splitting unit 600 may be connected to port X1 of splitting member 702. Port P3 of splitting unit 600 may be connected to port X2 of splitting member 702. Port P4 of splitting unit 600 may be connected to port Y2 of splitting member 704. Finally, port P2 of splitting unit 600 may be connected to port Y4 of splitting member 704.

Signal path SP1 may be directed from port P1, via splitting member 702, optical connection OC1 and splitting member 704 to port P2. Signal path SP2 may be directed from port P1, via splitting member 702, optical connection OC2 and splitting member 704 to port P4. Signal path SP3 may be directed from port P2 of splitting unit 600, via splitting member 704 to port P4. Signal path SP4 may be directed from port P3, via splitting member 702, optical connection OC1 and splitting member 704 to port P2.

Port Z1 of splitting member 706 may be connected with optical connection 284. Port Z3 of splitting member 706 may be connected with sending unit S2 within sending and receiving unit 250. Port Z3 of splitting member 706 may be connected with receiving unit R2 of unit 250. Splitting member 706 may be an integral part of unit 250 or may be a separate part thereof.

Sending and receiving unit 250 may comprise a forwarding unit FWU that may be connected to an output and/or to an input (node) of the transceiver unit TR2 and that may be connected to an output node of a video signal or video data receiving unit and/or that may be connected to the at least one interface unit IF. The forwarding unit FWU may be configured to forward the video signal or the video data to the interface unit IF or to another interface (for instance to an HDMI) and to forward control data that is received using the transceiver unit TR2 to the interface unit IF. The forwarding unit FWU may be configured to forward control data that is received using the interface unit IF to an input of the transceiver unit TR2.

Spoken with other words, a MRI (Magnetic Resonance Imaging) camera device 310 and/or signaling (communication) device 320 are disclosed:

1) The signaling (communication) device 320 may be based on multi colored light signals operating in MRI environment.

2) An integrated system 100, 200 consisting of or comprising the communication device according to 1) and/or an MRI compatible camera device 310, controlled by an MRI compatible control unit (230) comprising for instance a touchscreen and/or by a central control unit, for instance by a computing device (computer) in a technical room 294.

The communication and experiment control system may be dedicated to the use in an MRI environment. A system is disclosed that may allow performing novel methods of communication with a patient (subject) or other person (subject) during MRI and, especially, fMRI (functional MRI) procedures, as well as experiment control. An MRI environment may be challenging for electronic devices. Hence only a few solutions are offered on the market. Many clinical and research procedures may require the subject to perform specific tasks at a precisely defined time. The challenge is to provide the subject with information on e.g. when to start the task or when to stay still, i.e. not to make any movement. It may also be important to be able to verify if the subject performs the task in a correct manner. This may help to reduce the number of unsuccessful trials and, thus, reduce costs and time required for diagnostic or investigation process.

Another factor may be providing safety to the patient - MRI environment is stress-inducing, especially for people with for instance claustrophobia. MRI procedures are also often performed on patients in poor health condition, with likelihood of conditions such as seizures, arrhythmia or loss of consciousness. Thus it is important to monitor patients' state during the procedure and to be able to react to unpredictable situations.

Many MRI scanners 192 available on the market are not equipped with accessories that allow for the above stated monitoring.

The proposed solution may also be extended by an audio-based communications system. Audio-based communication systems provide a natural way of communication with the patient. The optical output device 320 may allow providing good synchronization for time-sensitive tasks. Camera device 310 may offer flexibility and may allow monitoring key parts of the subject's body, e.g. face or fingers.

An object of the disclosure is to provide an integrated system 100, 200 that allows inter alia for time-precise visual presentation of information to the subject and/or visual control of the subject's performance for a variety of procedures. Another key factor may be to allow easy and flexible control over the proposed functionality.

The object may be achieved using a system 100, 200 consisting of or comprising the at least two or all of the following features:

1) A communication interface (optical output device 120, 220) equipped with multicolored lights 320, used as communication signals. The interface (optical output device 120, 220) may be designed to be compatible with MRI device 192. This means that it is resistant to high magnetic fields and does not induce any artifacts to MRI image while operating inside the gantry of the MRI machine/device 192. The interface (optical output device 120, 220) may be integrated with other components of the disclosed system, especially with a camera device 110, 210, into a single enclosure or housing 304. The interface (optical output device 120, 220) may also work as a standalone device attached to the MRI machine/device 192 inside the gantry so that the patient has visual access to the interface (optical output device 120, 220). The role of the interface (optical output device 120, 220) is to present visual commands using various colors of light. Each color may have a meaning specified in the procedure, e.g. red color may mean “Remain still” (do not move), blue color may mean “Relax and wait for further instructions”, green color may mean “start performing a task”. Other meanings and/or colors are possible as well.

2) A camera device 110, 210, preferably integrated with communication interface or optical output device 120, 220 may be compatible with MRI and thus they may not introduce any artifact to the MRI image, even while working inside the gantry of the MRI device 192 or of the MRI machine. The camera device 110, 210 may be adjusted so that it can monitor the face of the subject, the chest of the subject, fingers of the subject or other parts of the subject's body, according to requirements of the procedure. The image from the camera device 110, 210 may be transmitted through optic fibers 272, 274 to technical room 294, where it can be visualized, recorded or analyzed on the external unit(s)/ computing device(s) 260. The external unit (for instance computing device 260 or cloud computers) may incorporate algorithms that allow automatic image recognition and analysis, e.g. recognition of facial expressions and/or breath-rate calculation based on chest movements.

3) An MRI compatible control unit 230 comprising for instance a touch-screen, mounted on MRI scanner device 192 or in a very close distance to the scanner device 192, which allows for easy setup of the communication interface device 320 (optical output device) and/or the camera device 310. Control unit 230 (comprising for instance the touch screen) may provide access to control buttons, preferably within a digital user interface UI, to setup image parameters and preview of the camera field of view.

Groups of patients that may especially benefit are: pediatric patients, sedated patients, patients with claustrophobia, patients at risk of an epilepsy attack, patients using sign language.

Applications are:

-   -   MRI diagnostic examinations. The proposed system may be designed         for all diagnostic examinations carried out in MRI scanners 192.         It may increase the safety and comfort of the subjects and may         minimize the costs generated by the need to repeat unsuccessful         tests.     -   fMRI examinations. Optical observation of hands, feet and other         parts of the patient's body may allow controlling the         correctness of the execution of commands (e.g. during the         examination of fMRI paradigms).     -   cardiac MRI examinations. Thanks to the proposed system it may         be possible to observe the chest and thus control whether the         patient's respiratory rhythm is synchronized with the heart         rhythm, which is very helpful in cardiologic MR examinations.     -   MRI examinations for people who do not speak, whose hearing is         impaired or who are deaf. Thanks to the possibility of observing         the hands, during the examination it may be possible to         communicate with people who do not talk, whose hearing is         impaired or who are deaf.

Benefits and capabilities are:

-   -   reduction of retesting: The scanner device 192 is a closed         machine and the tester is located in another room 294. Without         the proposed system it may not be possible to see if the         examined patient has open eyes and sees the displayed stimuli,         or whether they execute commands and if they execute them         correctly.     -   reduction of testing costs: Thanks to the camera device 110, 210         the number of failed tests and the need to repeat them may be         minimized. This may save money and time for patients and         healthcare professionals alike.     -   patient safety: Thanks to the camera device 110, 210 it is         possible to check if the patient's anxiety is not growing and to         control their well-being, possible panic attacks, epilepsy         attacks or fainting.     -   sedation examinations: It is very helpful during examinations of         adults and children in sedated state, allowing to control         whether the patient has not started to wake up.     -   comfort and legal aspect when examining children: The use of         camera device 110, 210 is particularly important for children.         It meets the legal requirement for a parent to be able to see         his or her child during the examination. It also increases the         psychological comfort of the parents, who can observe their         child during the MRI examination. It also helps to make the         experience easier for small patients.

Some possible technical parameters:

-   -   high-resolution color camera device 110, 210 (PAL/NTSC), and/or     -   interchangeable lenses (for instance from 13.5° (angle degrees)         to 160° opening angle), standard option: 120° for example,         and/or     -   built-in lamp/LED(s) with adjustable light intensity, and/or     -   video signal may be optically transmitted (e.g. via optical         fiber).

Other technical aspects:

-   -   functional housing 304 and frame 400 design to meet medical         standards, and/or     -   lightweight and easy to install structure, especially housing         304 and/or frame 400, and/or     -   possibility of convenient hanging of the camera device 110, 210         on the scanner's device 192 gantry, and/or     -   a tripod or stand or frame 400 that allows one to adjust camera         device 110, 210 position as desired, and/or     -   possibility of directing the camera device 110, 210 at any part         of the patient's body.

Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims. For example, it will be readily understood by those skilled in the art that many of the features, functions, processes and methods described herein may be varied while remaining within the scope of the present disclosure. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the system, process, manufacture, method or steps described in the present disclosure. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, systems, processes, manufacture, methods or steps presently existing or to be developed later that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such systems, processes, methods or steps. Further, it is possible to combine embodiments mentioned in the first part of the description with examples of the second part of the description which relates to FIGS. 1 to 7. 

1. System for communicating with a subject and/or for supervision of the subject during magnetic resonance imaging (MRI), comprising: a camera device that is configured to be placed within the gantry of an MRI device, and an electronic control unit that is configured to be placed within a distance less than 5 meters or less than 3 meters from the MRI device and/or from the camera device, wherein the electronic control unit is configured to control operation of the optical camera device, wherein the system further comprises: a receiving and sending unit, and an optical connection between the control unit and the receiving and sending unit, and wherein the receiving and sending unit comprises preferably: an optical sending unit, an optical receiving unit. a radio transceiver circuitry that is connected to optical sending unit and to the opticai receiving unit, and a) at least one interface unit to at least one computing device or b) alternatively at least one computing device, wherein the system is configured to transmit a video signal generated bv the camera device and control signals from the electronic control unit or from the receiving and sending unit using one single optical fiber of the opticai connection.
 2. System according to claim 1, comprising an optical output device for generating electromagnetic radiation in the visible spectral range that is configured to be placed within the interior space of the MRI device, wherein the optical output device is configured to be arranged within the field of view of a subject who is located within the gantry and wherein the optical output device is configured to send optical signals to the subject, and wherein the electronic control unit, is configured to control operation of the optical output device.
 3. System according to claim 2, wherein the camera device and/or and/or the optical output device and/or the control unit are MRI protected and/or compliant for an operation within or close to an MRI device by any one of, any arbitrarily selected plurality of some or all of the following measures: at least one current-source driven optoelectronic device of the optical output device or at least one voltage controlled current-source driven optoelectronic device, metal shielding of at least parts of the control unit and/or optical output device, image data transmission to and/or from the camera device through at least one optical fiber, control data transmission to and/or from the optical output device through electrical control lines with additional filter, control data transmission to and/or from at least one of the camera device or the optical output device through electrical control lines with additional filtering, electrical filtering on power lines for powering the optical output device and/or the camera device.
 4. System according to claim 1, comprising an optical connection between the camera device and the control unit, and/or an electrical conductive connection between the optical output device and/or the camera device on one side and the control unit on the other side,
 5. (canceled)
 6. System according to claim 1, wherein the radio transceiver circuitry is configured to perform a frequency shift keying preferably in the radio frequency range.
 7. System according to claim 1, comprising an optical splitting unit that comprises at least a first port, a second port, a third port and a fourth port, wherein the first port is configured to be connected or is connected to the or to an optical connection between the control unit and the camera device, wherein the second port is configured to be connected or is connected to the or to an optical connection between the control unit and and the receiving and sending unit, wherein the third port is configured to be connected or is connected to the control unit, wherein the fourth port is configured to be connected or is connected to the control unit, and wherein the optical splitting unit is configured to forward image or video data from the first port to the second port and/or to the fourth port, to forward control data from the third port to the second port and to forward control data from the second port to the fourth port.
 8. System according to a claim 1, comprising a power line between the control unit and the camera device, wherein the same power line is used for the optical output device.
 9. System according to claim 8, wherein the control unit comprises: an electrical sending unit, preferably configured to send data by modulating the voltage of the power line, an electrical receiving unit, preferably configured to receive data by evaluating the current flow through the power line, a transceiver circuitry connected to the electrical sending unit and to the electrical receiving unit preferably configured to implement a frequency shift keying (FSK) data transmission method or a method comprising FSK, preferably an optical sending unit, preferably an optical receiving unit, and preferably a radio transceiver circuitry connected to the optical sending unit and to the optical receiving unit, preferably configured to implement a FSK data transmission method or a FSK/amplitude shift keying (ASK).
 10. System according to claim 9, wherein the control unit comprises a control subunit that is configured to control the camera device and/or the optical output device and/or an illumination unit that is configured to illuminate a scene that is in the field of view of the camera device, wherein preferably the control subunit is connected to the electrical sending unit and/or to the electrical receiving unit and/or radio transceiver circuitry and wherein preferably the control unit comprises a touchscreen.
 11. System according to claim 10, wherein the control subunit is connected to the radio transceiver unit, wherein the control sub unit performs forwarding of control data received at the optical receiving unit and to the electrical sending unit.
 12. System according to claim 2, wherein the optical output device comprises: at least one low pass filter unit or at least two low pass filter units, wherein preferably at least one first low pass filter unit and at least one second low pass filter unit are connected in this order along the direction of the signal flow from the control unit to at least one optoelectronic device that is comprised within the optical output device and wherein preferably the first low pass filter unit has a higher cutoff frequency than the second low pass filter unit
 13. System according to claim 12, wherein the optical output device comprises at least one optoelectronic device that is configured to send the or at least a part of the optical signals to the subject, wherein the at least one optical output device comprises at least one current source that is voltage controlled, preferably based on an operational amplifier, wherein an output node of the at least one current source is connected to the at least one optoelectronic device and wherein an input node of the at least one current source is connected to at least one control signal and/or to an output node of the at least one low pass filter in the case in which only one low pass filter unit is is used or alternatively to an output node of the at least one second low pass filter unit.
 14. System according to claim 2, wherein the camera device and the optical output device are integrated into the same housing, wherein preferably an illumination unit is integrated into the housing, wherein the illumination unit is configured to illuminate the field of view of the camera device in order to enable taking optical images, wherein preferably the housing comprises: an electrical sending unit, preferably configured to send data by changing the load on the power line, an electrical receiving unit, preferably configured to evaluate changes of power voltage of the power line, a transceiver circuitry connected to the electrical sending unit and to the electrical receiving unit, preferably configured to implement a frequency shift keying (FSK) data transmission method or a method comprising FSK.
 15. (canceled)
 16. System according to claim 2, wherein the optical output device comprises at least one optoelectronic signaling device that is configured to send the optical signals or at least a part of the optical signals to the subject, wherein preferably the optical output device comprises at least three light emitting diodes (R, G, B) that are placed preferably within a space that is smaller than 0.25 square centimeters, and/or wherein the optical output device comprises at least one optoelectronic illumination device that is configured to illuminate objects or parts of the subject in the field of view of the camera device, preferably with white light or with infrared light.
 17. System according to claim 16, wherein the at least one optoelectronic signaling device is used for informative purposes of the subject.
 18. Camera module comprising: at least one first optoelectronic unit that is configured to output signaling light, a camera device, and a second optoelectronic unit that is configured to illuminate parts of a subject in the field of view of the camera device an electrical sending unit, an electrical receiving unit, an optical sending unit, wherein the camera module, is configured to receive control data via the electrical receiving unit and to control the camera device and/or the optoelectronic units according to the received control data, wherein the camera is configured to acknowledge control data or to generate control data and send the control data via the electrical sending unit, and wherein the camera module is configured to send optical signals or optical data generated by the camera device via the optical sending unit.
 19. Control unit comprising: a splitting unit, a display unit, an input unit, an electrical sending unit, an electrical receiving unit, an optical sending unit, an optical receiving unit, a radio transmitter unit that is connected to the optical sending unit and to the optical receiving unit, wherein the splitting unit comprises at least a first port, a second port, a third port and a fourth port, wherein the first port is configured to be connected to an optical connection between the control unit and a camera device, wherein the second port is configured to be connected to an optical connection between the control unit and a receiving and sending unit, wherein the third port is connected to the optical sending unit of the control unit, and wherein the fourth port is connected to the optical receiving unit of the control unit, wherein the splitting unit is configured to forward optical data from the first port to the second port and/or to the fourth port, to forward control data from the third port to the second port and to forward control data from the second port to the fourth port, wherein the control unit is configured to forward control data received at the second port to the electrical sending unit and to forward control data received at the electrical receiving unit to the second port, wherein the control unit is configured to show video data or image data received at the first port on the display unit, wherein the control unit is configured to send control data that is entered via the input unit via the electrical sending unit.
 20. Sending and receiving unit comprising: an optical sending unit, an optical receiving unit, a splitting member connected with the optical sending unit, the optical receiving unit und comprising an input/output port. a radio frequency transceiver circuit that is connected to the optical sending unit, a video signal or video data receiving unit that is connected to the optical receiving unit, at least one interface unit, and a forwarding unit that is connected to an output and/or to an input of the transceiver unit and that is connected to an output node of the video signal or video data receiving unit and that is connected to at least one interface unit, wherein the forwarding unit is configured to forward the video signal or the video data to the at least one interface unit and to forward control data that is received using the transceiver unit to the at least one interface unit, and wherein the forwarding unit is preferably configured to forward control data that is received using the interface unit to an input of the transceiver unit, wherein the sending and receiving unit is configured to receive the video signal or the video data and to send the control data using one single opticai fiber connected to the input/output port.
 21. Transmission system for transmitting video signals and control signals via an optical transmission connection, comprising: a first transmitter unit, that comprises an optoelectronic output element that converts an electrical signal into a light signal, a receiver unit4R2$ that comprises an optoelectronic input element having a specified electrical bandwidth, wherein the optoelectronic input element receives light and outputs an electrical signal, an optical transmission connection, arranged between the first transmitter unit and the receiver unit, a camera module that is connected to the first transmitter unit, an optional second transmitter unit that comprises an optoelectronic output element that converts an electrical signal into a light signal, an optional optical coupling unit that is coupled between the optional second transmitter unit and at least a segment of the optical transmission connection, and a radio frequency signal generation unit that generates a radio frequency signal using a control signal or control data and that has an output node which is connected to the first transmitter unit or to the optional second transmitter unit
 22. Usage of the transmission system according to claim 21 in the vicinity of an MRI device, wherein at least the first transmitter unit and/or the optional second transmitter unit, is/are located within a radius from the MRI device that is less than 10 meters or less than 5 meters.
 23. System according to claim 1, wherein the radio transceiver circuitry (TR2) is configured to perform an amplitude shift keying, preferably in the radio frequency range. 